Yacov, I don't see anything wrong with proms. I think many evening dresses could be more modest. I personally don't like to expose my arms at all. But that's just me. (My mother says I dress like a grandmother/nun.) Also, if the dancing is modest (as opposed to grinding against one another) I think it's fine. These are social events where young people can meet and socialize with one another.
Now if you really have a problem with mixed dancing, you have the option of either not going to a regular prom, or organizing a special Orthodox Jewish prom where the young men and women dance separately. All this talk of banning sounds rather extreme.
Finally, I don't think Nic meant any disrespect. He was just writing about his perspective on the whole prom thing. So please go easy on him.